Pneumatic die-cushion.



- cfWILLERs L N. 0. LAURIN..

PNEUMATIC DIE CUSHIQN.

APPLICATION man MAR. 19.

Patented Apr. 3Q, 19l8.

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Application filed March 19, 1.917. Serial No. 155,822.

To all who m t may concern Be it known that we, CARL WILLnns and Nine C.LAURIN, citizens of the United States ofAmerica, and residents ofChicago, county of Cook and State of' Illinois, have invented certainnew and useful Improve* ments in Pneumatic Die-Cushions, of which thefollowing is a specification.

Our invention relates to pneumatic die cushions, for use in stamping anddrawing presses, and has for its object improvement of such cushions.

Pneumatic cushions of the piston type are in common use at present. Thepresent invention is of the telescopic type and is illustrated by avertical central section in the accompanying drawing.

The lower telescopic member `1 is screwed into a lower plate or head 2,and the upper telescopic member 3 is similarly screwed into an upperplate or head 4. The outer surface of member 1, and the inner surface ofmember 3 are ground and fitted so as to make the joint between them asnearly air tight as is practicable in an operating device.

The upper end of member 1, on the part that is continually maintained inmember 3, is taperedoii" as shown at 5 to a thin edge. rlhe amount ofthis thinning of the metal of member 1 is enough to leave the remainingmetal of less strength thanwill withstand the normal air pressure usedin the chamber 10 inclosed by parts l, 2, 3 andv 4. In other words, ifthe shells 1 and 3 were as thin as the upper portion of the tapered part5, then they would giveaway under the mere pressure of the containedair. As so made the part 5 yields under the interior pressure to make anair tight joint after the manner of a leather gasket in an ordinarypump.

Extending axially through the device is a bolt or rod 6 which has itsupper end screwed into apart 7 which is a lixture connected to some partof the press, preferably the die shoes. A stuiing box 8 in the head 4makes an air tight joint around the rod 6.

The lower end of the rod passes through the head 2 and is threaded toprovide connections to a source of compressed air. An axial hole isdrilled in the lower end of rod 6 and is connected to a transverse hole9, 'Ihe channel thus formed serves as a passageway forcompressed airfrom the source to the chamber l Cn the rod 6 below the opening 9 andabove the plate 2 is a collar 11. This may be either a fixed collar oran adjustable nut. Bearing against the lower face of the collar 1.1 is awasher 12, and between the washer and the plate 2 is a packing 13. Theseparts, together with nut 14, washer 15 and packing 1G serve to securethe lower head 2 to the rod 6 and to make a tight joint at the point ofconnection.

For the purpose of facilitating the making of a. perfect alinementbetween the telescopic members 1 and 3, and the rod 6, the hole 17,through which the rod 6 passes, is made slightly larger than the rod,and the bearing surfaces 18 are made spherical. As a consequence, theadjacent surfaces of washers 12 and 15 are concave to match the surfaces18. As so made, the exact point of connection between. rod 6 and head 2is determined by the movement of head 4 on rod 6.

On the die or drawing rings are pins 20. As the die descends these pinsengage head 4 and force it downward on rod G. At the same time thetelescopic member 3`moves downward on member 1. This compresses the airin chamber 10, andthe excess pressure is relieved by air flowingbackward through hole 9 to the source of supply, which is usually a tankof compressed air. I/Vhen the pins 20 rise again, the air in chamber 10forces the head 4 upward until it engages the connection 7.

What weclaim is:-

specification of Leners raient. Patented Apr. 30,1913,

bers, heads secured to and closing the outer ends of said members, a rodextending through both heads, an air tight connection in one headarranged to permit a longitudinal movement of the head on the rod, andanother air tight connection between the rod and the other head, saidlast mentioned connection. being arranged to permit lateral and resistlongitudinal movement of head with respect to the rod.

2. In a pneumatic die cushion, telescopic members, heads closing theouter. ends of said members, a rod extending through both heads andhaving an interior passageway by which it serves as an inlet forcompressed air, air tight connections between said rod and said heads,one of said connections being arranged to permit longitudinal movementand the other` being arranged to perl g V Y v Y 1,264,731

respect to said rod, and a stop on said rod a stung box in the movablehead for the serving to limit the outward movementfof Vrod, and securingeonl'lections between said the longitudinally 'movablehead rod and thestationary head, said Connec- 10 3. vIn a pneumatic cushion, telescopicmemtions having curved surfaces substantially as 5 be1s5heacls securedto the'outer ends'of said and for the purpose speciied.

members, a rod extendingv through both CARL WILLERS. heads,one headbeing movable on said rod, NILS O. LAURIN.

' Copies of this patent may be obtained for ve cents each, by addressingthe Commissioner of Patents,

Washington, D. C.

